I cannot create a mesh (the dimensions are all set to 0 whenever i do try and create one)
I'm not sure but i might try to add new Objects (Create Tab -> Cylinder)

(Actually, I would use a torus )

and join the whole thing later on. (Ctrl+j)

Problems:

the object may need three different textures, one for one engine, one for the other, and one for the rest. (i had such issues, i don't know if that happens)